Field of the Invention
The invention refers to a carpet probe for detecting gas leaks in underground gas pipes.
Description of Related Art
The carpet probe is a flat, mostly flexible carpet-like element comprising a gas inlet which is connected to a gas sensor. The carpet element is attached to wheels and freely rotatable with regard to the wheels. The wheels are connected to a handle for pulling or pushing the probe along a ground surface below which a gas leak is assumed. The wheels roll on the ground surface and can be pulled or pushed. The carpet element thereby slides along the ground surface and possible gas escaping from an underground leak accumulates between the ground surface and the carpet and will enter the gas inlet. The gas inlet is typically a tapered opening in the centre of the carpet, the opening being connected to the gas sensor such that gas entering through the gas inlet will be detected by the sensor. The most important feature for collecting the highest amount of the gas escaping from the ground surface is ability of the carpet to stay as close as possible to the ground and be conformant to the ground. A gap between the carpet and the ground will allow wind and turbulence to blow away the gas before it is collected into the inlet. The bigger the gap the more gas is lost this way.
The multi-wheel configuration of known carpet probes limits their mobility, particularly on uneven terrain where the carpet probe needs to be lifted up from the ground surface for relocation. Upon lifting the carpet probe, the carpet will hang down from the wheels and handle because it is freely rotatable with regard to the wheels and handle. This is necessary in order to be able to either push or pull the carpet probe along the ground surface. Pushing the probe requires a different angle between the handle and the carpet element than pulling the carpet probe.